     (reduce -conj (btset) keys)))
 
 ;; helpers
-
 
 (defn parse-path [path shift]
   (loop [level shift

      (-write writer "\n")
      (dump (aget (.-pointers node) i) writer (str "  " offset)))))

(extend-type BTSet
  IPrintWithWriter
  (-pr-writer [o writer _]
    (dump (.-root o) writer "")))

;; (def s0 (into (btset) (shuffle (range 10000))))
;; (reduce disj s0 (shuffle (range 9995)))


;; perf

(def test-matrix [:target    { ;; "sorted-set" (sorted-set)
                               "btset"      (btset)}
;;                   :distinct? [true false]
;;                   :size    [100 500 1000 2000 5000 10000 20000 50000]
                  :size      [100 500 20000]
                  :method    { "conj"    (fn [opts] (into (:target opts) (:range opts)))
                               "disj"    (fn [opts] (reduce disj (:set opts) (shuffle (:range opts))))
                               "lookup"  (fn [opts] (contains? (:set opts) (rand-int (:size opts))))
